(Portland, OR)  --  Police say they've arrested a suspect in connection to last week's homicide near North Plains.  Police arrested 40-year-old Christopher Jay Stephens yesterday during a traffic stop in Tualatin.  Police say Stephens and 38-year-old Chad Brandon Pitcher were involved in the shooting death of Michael Arch at a home near Dairy Creek Road last Tuesday.  Police say Pitcher is still at large and should be considered armed and dangerous.